Screw-propeller and method of manufacture of the same.



D S. HEATH. SCREW PROPELLER AND METHOD OF MANUFACTURE OF THE SAME.

APPLIUATION FILED DEC.1,1908,

1,043,830. Patented Nov. 12, 1912.

2 SHEETSSHEET 1.

S. HEATH.

SCREW PROPELLER AND METHOD OF MANUFACTURE OF THE SAME.

APPLICATION FILED DEO.1, 1908.

Patented Nov. 12, 1912.

2 SHEETS-SHEET 2.

Q1 /Za SPENCER HEATH, OF WASHINGTON, DISTRICT OF COLUMBIA.

SCREW-PROPELLER AND METHOD OF MANUFACTURE 6F THE SAME.

Specification of Letters Patent.

Patented Nov. 12, 1912.

Application filed December 1, 1908. Serial No. 465,552.

To all whom it may concern.

Be it known that I, SPENCER HEATH, a citizen of the United States, and resident of Vashington, in the District of Columbia, have invented certain new and useful Improvements in Screw-Propellers and Methods of Manufacture of the Same, of which the following is a specification.

This invention relates to screw propellers and has for its object the production of.a

.propeller having the maximum of strength and rigidity with the least possible weight of material. It is intended for general use in any of the arts in which screw propellers (r screw fans or blowers are employed, but on account of its extreme lightness of construction is more especially adapted for use as a propeller in the art of aerial navigation.

With the above ,object of strength and lightness and the further object of so constructing the propeller as to secure, with accuracy, any desired and predetermined form of screw, I have invented a propeller and method of constructing the same which I shall describe in this specification by reference to the annexed drawings forming a part hereof, and in which:

Figures 1 and 2 are plan views of blanks from which the propeller may be formed.

Figs. 3, 4 and 5 are top, side, and bottom views respectively of a propeller formed from the blank of Fig. 1. Fig. 6 is an enlarged sectional view on line 66 of Figs. 3, 4 and 5. Fig. 7 is an enlarged sectional view on line 7-'-7 of Figs. 3, 4 and 5. Fig. 8 is a section corresponding to Fig. 7 when the propeller is formed from the blank of Fig. 2. Fig. 9 is a plan view illustrating my method of forming the material of the propeller into the requisite shape. Fig. 10 is a modified form of Fig. 1. Fig. 11 is a perspective view of Fig. 10 folded complete. Figs. 12, 13, 14, 15, 16 and 17 are sections taken J on lines 13-13, 1414, 1515, 16'16, and 1717 respectively of Figs. 10 and 11 Figs. 1%, 13 14 15 16 and 17 are sections similar to Figs. 12 to 17. Fig. 18 is a longitudinal end section of a folded blade. Fig. 19 is a section through the hub portion.

'Similar reference characters are used throughout to designate corresponding parts.

The propeller is formed into shape from a blank of sheet material, the central port-ion of which is formed or folded into a hollow portion or shell at and adjacentthe axis of the screw, and the other parts of which form the main portions of the blades or fans, the hollow central portion being extended along the back of the blades toward their extremities in such manner as to strengthen and stiffen them.

Referring to the drawings in Figs. 1 and 2, the apertures 10 at the center of the blank receive the propeller shaft. In constructing the propeller, a form or pattern 11 (Fig. 9) of fusible metal orother easily melted material is superposed upon the blank, as shown in Fig. 9, and the blank is shaped or spun closely to the pattern which is afterward melted out from the hollow portions, the crevices from which the molten pattern runs being afterward spun together and the seams brazed or riveted, if desired. The material is first bent or creased along the lines marked 12, the portions 13 being bent up against the faces 14 of the form to make the working surfaces or faces of the blades. The portion 16 at the center of the blank is bent over the center of the form inside of the portion 17 when it is then bent over the part 16 to form the hollow shell, as shown clearly in section by Fig. 6. The portions 18 which are extensions from 16 and 17 are bent over upon the back of the blades in such manner that the shell formation of the center is extended along one edge of the used and both edges of theblades will be reinforced, as shown clearly by Fig. 8.

When the material has been formed into shape, it may be brazed or soldered along the lines 1.9 and 20,if desired, but this has been found not always necessary, especially in the smaller sizes,- since the metal has sufficient stiffness and rigidity to protect the hollow portion from distortion when simply folded together without further means of security. This feature is of special value where it is desired to use aluminum or some of its compounds which are only with great difficulty capable 01 being brazed or soldered. Should it be desirable to fasten this material, however, it may be doneby means of small rivets along the edges to be secured. After the central portion has been formed into the hollow shape, a hole 21 for the shaft 'ismade in the portions 16 and 17 opposite thehole 10. The shaft may be brazed or otherwise secured directly to the metal surrounding these holes or a tube 22 may be secured therein and the shaft keyed or otherwise fastened in the tube.

A propeller constructed in the manner that I have described can be made in very accurate form while employing in its central or hub portion a sectional area of material which may be greater than that of any other part, and this material is so formed and disposed as to give the maximum of strength and rigidity. The central shell portion may be extended toward the extremities of the blades to any extent desired by simply enlarging the portions 18, even giving the blades a double or triple thickness throughout, if desired. Where only one edge of the blade is reinforced, it should be the forward edge, which is then stiffened after the manner of a quill in a wing feather, and the unreinforced portion of the blade may be left somewhat flexible, after the manner of that portion of the wing feather lying back of the quill.

The modification of Fig. 1 shown in Fig. 11 posseses the same corresponding parts and general characteristics as Fig. 1, the relative proportions of the parts being changed so that when the propeller is folded along the line 12 and formed to the shape of its pattern it will have the appearance shown in Fig. 11. The sections in Figs. 12 to 17 show how the front portions 13 of the blades have the back reinforcing portions 18 bent over upon them and joined by the lapping seam '19 at the hub portion and its continuations in the longitudinal seam 20. In Figs. 12 to 17 there is a slight change in the manner of lapping for the seam. Fig. 19 shows amore enlarged hub portion than Fig. 6 with the enlarged reinforcing member 22 for the shaft connection.

Having now fully described several of the forms in which my invention may be embodied and indicated clearly the principle thereof, what I claim is:

1.-A propeller formed from a blank of sheet material folded longitudinally in such manner as to give multiple thickness to its.

parts.

2. A propeller formed from a blank of sheet material and having blades with reinsheet material having extensions thereon adapted to reinforce its center and blades.

4. A propeller formed from a blank of sheet material and having two blades with extensions on the center and blade portions adapted to strengthen the blades and form a hollow central portion. I

5. A propeller having a hollow shell-like central portion, said shell-like central portion being extended toward'the extremities along the edges of the blades.

6. A propeller formed from a blank of sheet material and having a hollow shelllike central portion and extensions on the sides of the blades bent back to reinforce them.

7. The method of forming hollow propellers of sheet material which consists in forming the propeller of sheet material over a.

form or pattern of easily fusible material having the requisite shape, and then melting said fusible material and causing it to run out of the hollow portions of the propeller.

8. A propeller of hollow construction formed from sheet material pressed to the requisite shape and joined by a longitudinal seam extendlng from end to end of the propeller.

9. A propeller of hollow construction formed from sheet material to the requisite shape and joined by a longitudinal seam extending from end to end of the propeller and a reinforcing member secured in the center of the propeller for its shaft connection.

10. A propeller formed from a blank of sheet material folded longitudinally at its central portion to form the hub, the longitudinal folds being extended to the opposing blades to reinforce them.

11. A propeller formed from a blank of sheet material folded longitudinally at its central portion to form a hub of hollow construction, the folds and hollow, construction being extended throughout the length of the blades.

12. A two bladedpropeller formed from a single blank of sheet material extending from end to end of the blades, the blank of material being longitudinally folded to form hollow blades with a hollow central portion connecting them.

SPENCER HEATH.

Witnesses ROLAND G. Boo'rrr, CHAS. E. DIGKERSON. 

